Spinal fusion system utilizing an implant plate having at least one integral lock

ABSTRACT

Spinal fusion system utilizing an implant plate having at least one integral lock.

RELATED APPLICATION DATA

This application is a continuation-in-part of U.S. patent application Ser. No. 10/858,629, filed Jun. 2, 2004, which is a continuation-in-part of U.S. patent application Ser. No. 10/675,361, filed Sep. 30, 2003, both of which are incorporated herein by reference and made a part hereof.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a veritable prosthetic system and device and a method for implanting the device and, more particularly, to a spinal fusion system and method for fusing spinal bones.

2. Description of the Related Art

Many types of prosthetic devices have been proposed in the past. For example, U.S. Pat. No. 5,192,327 to Brantagan concerns a surgical prosthetic modular implant used singularly or stacked together to support and fuse together adjacent vertebrae or to totally or partially replace one or more vertebrae in a vertebral column. Other surgical implant devices and methods are shown in U.S. Pat. Nos. 5,192,327; 5,261,911; 5,713,899; 5,776,196; 6,136,002; 6,159,245; 6,224,602; 6,258,089; 6,261,586; 6,264,655; 6,306,136; 6,328,738 and 6,592,586. Some or all of these devices have improved the success rate and have simplified the surgical techniques in inter-body veritable fusion.

Among some of the problems associated with the prior art devices is that after the device is inserted into a patient during a surgical procedure, there was a possibility of retropulsion of the inter-body device and graft material into the spinal cord or other neurological element.

Another problem with the prior art devices is that grafting material, which was inserted into the devices during the surgical procedure, could not easily be inserted from an anterior direction.

Moreover, in some of the prior art devices, the cover, if any, was typically fastened directly to the device and to spinal bones, which prevented the cover from being capable of moving relative to the device. In addition, in devices that used a cover, the cover did not function to both retain the grafting material in the device and simultaneously fix the spinal bones relative to each other.

Another problem with prior art cage systems is that the screws or fasteners which secured the cover onto the cages sometimes had a tendency to unscrew themselves which is undesirable because the graft material may exit the cage or because the cage itself may move. Another problem is that the screws may withdraw, causing injury to local structures by the screws themselves.

What is needed, therefore, is a system and method, which facilitates overcoming one or more of the aforementioned problems as well as other problems and to provide a device that has unique features that will facilitate reducing the risk associated with neurological surgeries and advance the present state of the art.

SUMMARY OF THE INVENTION

It is, therefore, one object of the embodiments to provide a plate having an integral lock.

Another object of one embodiment is to provide a plurality of screws that are capable of locking to facilitate preventing the fasteners to become unfastened or unscrewed.

Another object of the invention is to provide fasteners at least one of which has an eccentric to facilitate locking against an adjacent fastener in order to retain the fasteners and the cover in a locked position.

In one aspect this invention comprises an implant plate comprising a plate member having a plurality of apertures, each of said plurality of apertures being capable of receiving a screw, a plurality of resilient members having a locking portion in operative relationship with said plurality of apertures, respectively, and each of said plurality of resilient members retaining or maintaining said screw in a locked position.

In another aspect this invention comprises an implant plate comprising at least one aperture and at least one integral lock associated with said at least one aperture for preventing a screw received in said at least one aperture from withdrawing from said plate.

In still another aspect this invention comprises an implant plate comprising a plate member having a plurality of screw-receiving areas, each of said plurality of screw-receiving areas being capable of receiving a screw and a plurality of locking fingers associated with said plurality of screw-receiving areas, respectively, each of said plurality of locking fingers being capable of retaining said screw in at least one of said screw receiving areas.

In still another aspect this invention comprises an implant system comprising a plate member having a plurality of screw-receiving openings, a plurality of locking fingers adjacent said plurality of screw-receiving openings, respectively and a plurality of screws received by said plurality of screw-receiving openings, respectively, and retained in said plate member by said plurality of locking fingers.

In still another aspect this invention comprises an implant plate system comprising a plate member; and a plurality of locks integrally formed in said plate member for retaining a plurality of screws, respectively, in said plate member.

In still another aspect this invention comprises a prosthetic implant plate comprising a generally planar member and an integral lock for preventing withdrawal of at least one screw after said at least one screw is screwed into a spinal bone.

These and other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial side view a human spine illustrating anteriorly discs between various spinal bones;

FIG. 2 is a partial side view of the spinal column shown in FIG. 1 illustrating several of the discs removed, for example, after surgical procedure;

FIG. 3 is a partial side view of the human spine with the housings according to one embodiment of the invention situated therein;

FIG. 4 is a partial side view of the human spinal column illustrating graft material being inserted anteriorly into the housing;

FIG. 5 is a partial exploded side view of the embodiment shown in FIG. 1-4 illustrating a cover and a plurality of screws which will secure the cover to the spinal column;

FIG. 6 is a side view similar to FIG. 5 illustrating after the cover has been mounted to the spinal column;

FIG. 7 is a exploded view of the device shown in FIG. 6, illustrating a plurality of housings and a single cover for use with covering the plurality of housings;

FIG. 8 is partial side view illustrating an elongated housing and cover used during a vertebrectomy procedure;

FIG. 9 is a partial side view of the spinal column illustrated in FIG. 8 showing the elongated housing situated between adjacent spinal bones in a single cover to be affixed to those spinal bones;

FIG. 10 is an exploded view of the circle area shown in FIG. 8;

FIG. 11 is a exploded view of the elongated housing illustrated in FIGS. 8 and 9 and the cover and screws associated therewith;

FIG. 12 is a partial fragmentary view of the cover and housing after the cover has been situated between a pair of rails associated with the housing;

FIG. 13 illustrates a partial side view of an embodiment showing a plurality of housings of different sizes used with a single cover;

FIG. 14 is a exploded view of the housings and cover illustrated in FIG. 13;

FIG. 15 is a partial anterior side view a human spine illustrating the discs between various spinal bones;

FIG. 16 is a partial anterior view of the spinal column shown in FIG. 1 illustrating several of the discs removed, such as by surgical procedure;

FIG. 17 is a partial anterior view of the human spine with the housings according to one embodiment of the invention situated therein;

FIG. 18 is a partial anterior view of the human spinal column illustrating graft material being inserted anteriorly into the housing;

FIG. 19 is a partial exploded anterior view of the embodiment shown in FIG. 1-4 illustrating a cover and a plurality of screws for securing the cover to the spinal column;

FIG. 20 is a anterior view similar to FIG. 5 illustrating the cover mounted to the spinal column;

FIG. 21 is a fragmentary view illustrating various features of the cover;

FIG. 22 is another fragmentary view of the cover after the screws are mounted and the locking mechanism retains the screws therein;

FIG. 23 is a fragmentary sectional view of the embodiment shown in FIG. 22 illustrating various features of the locking mechanism;

FIG. 24 is a schematic view of a process or method in accordance with an embodiment of the invention;

FIG. 25 illustrations another embodiment of the invention without crossbars or migration preventers;

FIG. 26 is a view of another embodiment of the invention showing the crossbars integrally formed in the housing and without migration preventers;

FIG. 27 is a view illustrating a plurality of migration preventers, without any crossbars;

FIG. 28 is a view illustrating a housing with a plurality of projections which cooperate with the cover to prevent the housing from migrating anteriorly;

FIG. 29 is another view of the housing illustrating a plurality of removable crossbars without any migration preventers;

FIG. 30 illustrates another embodiment of the invention, similar to the devices illustrated earlier relative to FIG. 1-20 showing details of the cross bars and notches for receiving them;

FIG. 31 is a view of a housing having walls having recessed areas for receiving the cover;

FIG. 32 is a view of another embodiment of the invention showing the plurality of fasteners or screws in an unlocked position;

FIG. 33 is a view of the fasteners or screws shown in FIG. 32 in a locked position;

FIG. 34 is a view taken along the line 34-34 in FIG. 32;

FIG. 35 is a view taken along the line 35-35 in FIG. 33;

FIG. 36 is an exploded view of the other embodiment of the invention with the locking screws illustrated in FIGS. 32-35;

FIG. 37 is perspective view of another embodiment of the invention;

FIGS. 38A-38E are various views of the embodiment shown in FIG. 37, illustrating various details of the embodiment shown in FIG. 37;

FIGS. 39A-39I are various fragmentary and sectional views illustrating the integral lock, detent or resilient finger for retaining or maintaining a screw in a lock position in the spinal bone;

FIGS. 40A-40D illustrate another embodiment of the invention showing two pairs of apertures and associated resilient fingers, detents or integral locks;

FIGS. 41A-41D is still another embodiment in the invention showing three pairs of apertures and resilient fingers, detents or integral locks;

FIGS. 42A-42D illustrate another embodiment of the invention showing five pairs of apertures and associated resilient fingers, detents or integral locks;

FIGS. 43A-43D illustrate another embodiment of the invention for the plate having a single screw per spinal bone application; and

FIGS. 44A-44D illustrate yet another embodiment illustrating a single aperture or a single screw per spinal bone for an application that contemplates the use of a single screw in each of three spinal bones.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring now to FIG. 1, a partial side view of a patient or person P is shown having a spinal column S and a plurality of spinal bones, such as vertebrae, 10, 12, 14 and 16. Note that a disc, such as discs 18, 20 and 22 in FIG. 1, is located between adjacent pairs of spinal bones (e.g., between bones 10 and 12, 12 and 14, and 14 and 16). During a spinal fusion procedure, such as a discectomy, the discs 18, 20 and 22 may be removed so that adjacent vertebrae may be fused together

FIG. 2 illustrates a fragmentary view of the spinal column S shown in FIG. 1, with the discs 18, 20 and 22 removed. It should also be understood that during another surgical procedure, such as a vertebrectomy, it may be desired to remove part of all of one of the spinal bones 10-16, as illustrated in FIG. 13. In this type of neurological procedure, it may also be desired to fuse adjacent spinal bones together for reasons that are conventionally known. This invention provides means for facilitating and performing such procedures. For ease of illustration, FIGS. 15-20 provide corresponding anterior views to the side views shown in FIGS. 1-6, respectively.

In the embodiment being described, a spinal fusion system 24 is provided for use as a prosthetic implant during a neurological procedure such as the aforementioned vertebrectomy or discectomy. In general, after the discs 18, 20 and 22 (FIG. 1) are removed, as illustrated in FIG. 2, a plurality of receiving areas 26, 28 and 30 (FIGS. 2 and 17) are defined by the areas between the surfaces of adjacent spinal bones 10, 12, 14 and 16. As illustrated in FIG. 2, the area 26 is bounded in part by the surface 10 a of spinal bone 10 and surface 12 a of spinal bone 12. Likewise, area 28 is partially bounded by surface 12 b of spinal bone 12 and surface 14 a of spinal bone 14, and area 30 is bounded by surface 14 b of spinal bone 14 and surface 16 a of spinal bone 16.

As illustrated in FIGS. 3-7 and 11 and as will be described in more detail later herein, the spinal fusion system 24 comprises a housing 32 dimensioned to be situated or received between adjacent spinal bones, such as bones 10 and 12. A housing 32 is situated in each of the plurality of receiving areas 26, 28 and 30, as illustrated in FIGS. 3-4. Each housing 32 cooperates with adjacent spinal bones to define a graft area, such as areas 34, 35 and 36 in the view illustrated in FIG. 17, for receiving graft material 38 (FIGS. 4 and 18). As illustrated in FIGS. 4 and 18, the graft material 38 is situated in the areas 34, 35 and 36 after placement of the housing 32.

As illustrated in FIG. 11, the housing 32 is generally U-shaped as shown. In the embodiment being described, the housing 32 comprises a well 33 defining multiple sides and comprises a predetermined shape selected to cause the graft material to be formed into a multi-sided fused coupling between adjacent spinal bones, such as bones 10 and 12 in FIG. 3. Although not shown, the housing 32 could define a shape other than rectangular, such as semi-circular, oval or other suitable shape as may be desired. Note that the housing 32 comprises a first wall 32 a, a second wall 32 b and a third wall 32 c joining the first wall 32 a and the second wall 32 b. One or more of the walls 32 a-32 c may comprise a plurality of holes or apertures 40 which facilitate the fusing process. The apertures 40 also permit visualization of graft material 30 on x-rays.

As mentioned later herein, the predetermined shape defined by the spinal fusion system 24 may provide a fused multi-sided plug of fusion material 32 having a height H (FIGS. 14 and 16) of at least two millimeters, but typically less than approximately 180 millimeters. This height H may vary depending on the vertical size or height H (as viewed in FIG. 16) of the areas 26-30 to be filled. For example, in the area 26 illustrated in FIGS. 2, 14 and 16, the height H of the area 26 generally corresponds to a height H1 (FIG. 1) of a disc, such as disc 18. Thus, the fusion material 38 (FIG. 18) would resultantly have a fused height H2 (FIG. 18) that generally corresponds to the height H (FIG. 16) and height H1 (FIG. 1). If, for example, a housing 32 having a longer height is required, such as height H3 in FIG. 14 and height H4 in FIG. 13, such as in the event of a vertebrectomy, then the fusion system 24 and housing 32 will define a height that generally corresponds to the dimension or height H (FIG. 9) to be traversed. Thus, it should be understood that the dimensions of the generally U-shaped housing 32 of the spinal fusion system 24 is selected depending on the size of the area 26-30 to be filled and the environment or application in which the spinal fusion system 24 is used. In general, the width and depth of the housing 32 will be approximately 9-20 millimeters and 7-20 millimeters, respectively.

As illustrated in FIGS. 5-7, 11, 14 and 21-22, the spinal fusion system 24 further comprises a cover 42 comprising a plurality of apertures 44 that receive a plurality of screws 46, respectively, which are screwed directly into the spinal bones 10 and 16, as illustrated, for example, in FIGS. 5-6.

As illustrated in FIG. 11, the housing 32 comprises a first rail, channel wall or wall portion 48 and a second rail, channel wall or wall portion 50 which cooperate to define a channel area 52 for receiving the cover 42. It should be understood that when the cover 42 is received in the channel 52, the sides 42 a and 42 b become associated with the sides 48 a and 50 a. It should be understood that the cover 42 is not directed permanently secured to the housing 32 after it is received in channel area 52. This feature permits the housing 32 secured to the housing 32 to migrate or float relative to the cover 42 even after the cover 42 is fixed to one or more of the spinal bones 10-16 as illustrated in FIGS. 6 and 20. As illustrated in FIG. 23, the edges 42 a and 42 b of cover 42 and sides 48 a and 50 a may be beveled and complementary to facilitate locating and mating engagement between the cover 42 and housing 32.

As illustrated in FIGS. 3-6 and 16-20, after the graft material 38 is placed in the housing 32 and the graft areas 35-36 (FIG. 17) defined by the housing 32 and adjacent spinal bones, then the cover 42 is situated between the walls or rails 48 and 50, as illustrated in FIGS. 6 and 19. The screws 46 may then be used to secure the cover 42 to one or more of the spinal bones 10-16 as illustrated in FIGS. 6 and 20. It should be understood that a feature of the invention is that the cover 42 facilitates aligning the housings 32 in a substantially co-lineal or relatively aligned position relative to each other and to the spinal bones 10-16, as illustrated in FIGS. 6, 19 and 20. In the setting of multiple level discectomy, the floating cover 42 allows limited, controlled settling of the cages or housings 32 in the vertical plane with respect to the cover 42. As illustrated in FIGS. 6, 8, 10 and 20, the cover 42 also provides means for providing a mechanical fixation of the adjacent spinal bones 10-16 relative to each other. Thus, while the housing 32 cooperates with adjacent spinal bones, such as spinal bones 10 and 12, to define a graft receiving area 34, the cover is multi-functional in that it not only covers the opening of any graft areas, such as area 34 (FIG. 17), but it also secures and retains the spinal bones 10-16 in a fixed spatial relationship relative to each other and relative to the housings 32. It should also be understood that the cover 42 may be fixed to one or more of the spinal bones 10-16 as may be desired to accomplish either of the aforementioned functions.

As illustrated in FIG. 11, note that the walls 48 and 50 further define projections 48 b, 48 c, 50 b and 50 c as shown. As illustrated in FIGS. 3-6 and 17-20, the projections 48 b, 48 c, 50 b and 50 c provide a plurality of migration preventers for preventing the housing 32 from migrating posteriorly in the direction of arrow A (FIG. 3) toward the spinal cord S or other neurological elements after the housing 32 is situated between the adjacent spinal bones 10-16 as illustrated. Further, the migration preventers 48 b, 48 c, 50 b and 50 c enable a surgeon to locate each housing 32 between adjacent spinal bones, such as spinal bones 10-16 in FIG. 1, and move the housing 32 in the direction of arrow A in FIG. 3 until the migration preventers 48 b, 48 c, 50 b and 50 c engage the surface 10 a of spinal bone 10 and migration preventers 48 b, 48 c, 50 b and 50 c engage the surface 12 a of spinal bone 12. As illustrated in FIG. 3, after the housings 32 are situated between the spinal bones 10-16 as shown, the migration preventers 48 b, 48 c, 50 b and 50 c facilitate preventing the wall 32 c from being over-inserted by the surgeon or from being over-inserted to a point where it engages the spinal cord S or other neurological elements.

The spinal fusion system 24 further comprises at least one migration stop or crossbar 60 as illustrated in FIGS. 11, 12, 29 and 30. The crossbar 60 may be either integrally formed in housing 32, as shown in FIG. 26, or separate as illustrated in FIGS. 11, 29 and 30, as illustrated in FIGS. 7, 12 and 14, for example. As illustrated in the exploded view in FIGS. 10 and 11, the surface 60 a of crossbar 60 engages and cooperates with surface 42 c of cover 42 to prevent anterior migration in the direction of arrow B). Thus, the spinal fusion system 24 of the embodiment being described provides means for preventing insertion of the housing 32 to a point where it might engage the spinal cord S (FIG. 3) or other neurological elements, such as dura mater, thecal sac, and also means for facilitating prevention of migration of the housing 32 in an anterior direction or in the direction of arrow B in FIG. 10 after the housing 32 is situated as described herein and the cover 42 is mounted to one or more of the spinal bones 10-16.

It should be understood that a plurality of the migration stops or cross bars 60 may be used alone or in combination with the migration preventers 48 b, 48 c, 50 b and 50 c. It should be understood that the stops 60 could be detachable, as shown in FIG. 26, or they could be integrally formed in housing 32 (as shown in FIG. 26). Also, these cross bars 60 may be removably received in the notched receiving areas 94 (FIGS. 29-30). For example, in anatomy that provided limited space, the surgeon may elect not to use housing with cross bars 60 or use a housing that does not have integrally formed cross bars.

The system 24 further comprises a system or means for preventing retraction or back out of the screws 46 after they are screwed into the spinal bones 10-16 in order to secure the cover 42 thereto. The spinal fusion system 24 of the present invention may be used with conventional screw lock devices or with a unique locking mechanism and system, which will now be described relative to FIGS. 21-23.

As illustrated in FIGS. 21-23, the spinal fusion system 24 and, more particularly, cover 42 may be provided with at least one or a plurality of resilient detents 62 which are generally L-shaped as shown and are resilient so that they can move laterally in the direction of double arrow C in FIGS. 21-22 towards and away from a home position (FIG. 21) to permit the screws 46 first received in the apertures 44, and, second, locked into the cover 42. Thereafter, the screws 46 may be screwed into a spinal bone, such as spinal bone 10, and when a screw head 46 a of the screw 46 engages a detent portion 62 a of the resilient lock 62, the resilient lock 62 moves in a direction away from the apertures 44 until the screw head 46 a clears the portion 62 a. After a top surface 46 b of the screw head 46 a has cleared the bottom surface 62 a 1 (as viewed in FIG. 23) of portion 62 a, the resilient lock 62 moves back toward aperture 44 to the home position until the portion 62 a and surface 62 a 1 are operatively positioned over surface 46 b of screw 46, thereby retaining and preventing the screws 46 from backing out of the cover 42 and thereby preventing the screws 46 from backing out of the spinal bone 10.

In the embodiment being described, the components of the spinal fusion system 24, such as the housing 32, first channel wall portion 48 and second channel wall portion 50, crossbar 60, cover 42 and screws 46 may be made of any desired composition or material such as a polymer, composite polymer, titanium, stainless steel, carbon fiber or other suitable material.

A method for fusing spinal bones together will now be described relative to FIG. 22. It should be understood that this procedure may be used during a vertebrectomy or discectomy or other neurological procedure during which it is desired to fuse spinal bones together. For ease of illustration, the embodiment will be described as used during a discectomy procedure during which the discs 18-22 (FIG. 1) are removed so that spinal bones 10-16 may be fused together. The procedure begins by situating a patient P on an operating table (not shown) and providing an appropriate incision as conventionally known to expose the spinal bones such as the bones 10-16 illustrated in the side view shown in FIG. 1 and in the anterior view illustrated in FIG. 15. (Block 70 in FIG. 22). At Block 72, the vertebrae or discs, such as discs 18-22 in FIGS. 1 and 15, are surgically removed revealing the areas 26-30 in FIGS. 2 and 16. At Block 74, the housings 32 are inserted in the direction of arrow A (FIG. 3) into the areas 26, 28 and 30 until the migration preventers 40 b, 48 c, 50 c and 50 d engage the surfaces of the spinal bones 10-16, such as the surfaces 10 a and 12 a illustrated in FIG. 3. (Block 74 in FIG. 22). As mentioned earlier herein, the migration preventers facilitate preventing inserting the housing 32 to a point which would cause the wall 32 c to engage the spinal column S.

As illustrated in FIGS. 3 and 17, the housing 32 cooperates with adjacent spinal bones, such as bones 10 and 12 to define the graft receiving area or cavity 34 in which the graft material 38 (FIG. 4) may be inserted. As mentioned earlier herein, these graft areas 34-36 may comprise a shape which is generally rectangular, as defined by the shape of the housing 32, but it could comprise another shape by simply providing a housing 32 having a different predetermined shape. Thus, the housing 32 may be provided in a circular or arcuate shape in which case the graft area 34 would define a generally circular or arcuate area, which would cause the graft material to form a similar shape. Other curved or multi-sided shapes may be defined by providing an appropriately or correspondingly shaped housing 32, depending on the selected or desired shape that the physician would like the fused graft material 38 to assume after it has fused to the adjacent spinal bones.

At Block 76, the graft material 48 is inserted and at Block 78, the cover 42 is situated in the slot or area 52 defined by the walls 48 and 50. As mentioned earlier herein, the cover 42 facilitates covering the openings, such as openings 34 a and 36 a of the graft areas 34 and 36, respectively. The surgeon secures the cover 42 to one or more of the bones, as illustrated in FIGS. 5-6 and 19-20 and then closes the patient (Block 80).

Again, and as mentioned earlier, a feature of the invention is that it provides a fixing system for fixing the location of the bones 12-16 relative to each other. Simultaneously, the system 24 permits the housing 32 to “float” between adjacent bones, such as bones 10 and 12 in FIGS. 3 and 6. This is advantageous for reasons mentioned earlier herein. Another advantage on this feature of the invention is that if it is necessary to operate on the same patient at a later time (Block 82 in FIG. 24) and, for example, add one or more housings 32 in order to fuse other spinal bones together, then the cover 42 can simply be removed at a later time, another discectomy or vertebrectomy performed and another housing 32 inserted. Another cover 42, or perhaps a second cover may then be used to seal the additional housing 32 after it is situated in the manner described herein. Thus, this invention provides a system and method, which is flexible and will permit the addition or insertion of additional housings 32 of the same or different sizes during a second operating procedure as illustrated in Block 82.

FIGS. 1-8 and 15-20 illustrate the general procedure and use of the invention in an illustrative discectomy wherein three discs are removed, replaced with housing 32, and graft material 38 inserted as described and cover 42 situated and mounted as described herein. In the illustration shown in FIGS. 1-8 and 15-20, three discs 18-22 are removed and the spinal bones 12-16 are fused together using the system and method as shown and described. It should be appreciated, however, that this system and method may be used with fewer or more housings 32 and with one or a plurality of covers 42 as may be desired or required. For example, if only one of the discs 18-22 needed to be excised and only two of the spinal bones 10-16 fused together, then only one housing 32 and cover 42 may be necessary. Likewise, as mentioned earlier herein, the housings 32 may comprise a different dimension or different height H (FIG. 14) to span a greater area, such as the area H4 illustrated in FIGS. 13 and 14. For example, FIGS. 13 and 14 illustrate a vertebrectomy wherein the spinal bone 12 has been removed along with the disc between spinal bones 14 and 16. This provides areas 80 and 81 in which an elongated housing 32′, such as the housing 32′ illustrated in FIG. 14 may be inserted. After the housings 32 and 32′ are inserted between the spinal bones 10-14 and 14-16 as shown in FIG. 13, graft areas 82 and 84 are provided for receiving the graft material 38. As illustrated in FIG. 13, the cover 42 would have a corresponding elongated shape for fixing the bones 10 and 14 together and for covering both openings 82 and 84 or housings 32 and 32′.

It is also anticipated that the invention may be used in a multitude of procedures, such as a vertebrectomy (FIGS. 8 and 9), discectomy (FIGS. 1-7, 13-20, or even a combination of a vertebrectomy and discectomy as illustrated in FIGS. 13-14. As mentioned and described earlier herein, a combination of different sizes of housings 32 and covers 42 may be used as shown. Although it is preferred that a single cover 42 be used, it may be desired in some applications to use multiple covers 42, such as where the removed discs are not adjacent.

In the illustrations being described, the housings 32 comprise the crossbar 60 which cooperate with the cover 42 to prevent anterior migration of the housing after the screws 46 are secured to the spinal bones as illustrated in FIGS. 6, 9 and 13.

FIGS. 25-30 illustrate other embodiments of the invention. In FIG. 25, a generally U-shaped housing 32 is provided without the walls 48 and 50 or crossbar 60. This embodiment may be useful. This may be useful if it were desired to insert housing 32 in local anatomy so that it could be loaded from the side or laterally, rather than anteriorly, as previously described.

In FIG. 26 a housing 32′″ is provided with the crossbars 60, but without the walls 48 and 50. In this embodiment it may be useful to use such a housing design when the local anatomy provides limited space.

FIG. 27 illustrates yet another embodiment of the invention illustrating a housing 32 that is provided with a plurality of protrusion 86, 88, 90 and 92 that do not span completely between the walls 32 b or 32 a together but yet provide the protrusions 86-92 which will engage the cover 42 if the housing attempts to migrate anteriorly as described earlier herein. FIGS. 1-24, 29 and 30 show embodiments of the invention where the crossbars 60 are not integrally formed with the housing 32, but received in the notched areas 90 as shown. As mentioned earlier, the crossbars 60 may be separate or may be integrally provided with the housing 32. Providing detachable crossbars 60, such as is shown in the embodiments illustrated in FIGS. 25, 28 and 29, enable the walls 32 a and 32 b to flex towards and away from each other. The housing 32 may be provided with a malleable material in which case the surgeon can change the general U-shape of the housing 32 to accommodate the size or shape of the areas 34 and 36 (FIG. 17). In the embodiment described, housing 32 and cover 42 may be made of titanium, polymer or a bioresorbable material.

FIG. 31 illustrates the walls 48 and 50 having notched areas 49 and 51 for receiving the cover 42 which is dimensioned to fit, thereby eliminating the need for cross bars 60.

FIGS. 32-36 illustrate another embodiment of the invention. In this embodiment, those parts that are the same or similar to the parts illustrated in FIGS. 1-30 are identified with the same part number. except that the parts in FIGS. 31-36 have an apostrophe (“'”) mark added thereto.

In this embodiment, the cage system 10 comprises a cover 400 for situating in the channel area 52 (FIG. 11) to facilitate preventing interior migration of the graft material 38. In order to secure the cover 400 over the graft area 38, a locking system, means and method are provided for retaining the cover 400 on the housing 32. In the embodiment being described, the locking system 402 comprises a plurality of screws, fastening means or fasteners 404, 406, 408 and 410 that are received in openings, such as openings 405 in the cover plate 400 as shown. Note that the fasteners 404-410 comprise a plurality of female openings or slots 404 a, 406 a, 408 a and 410 a for receiving a tool, such as a hex wrench for tightening and loosening the fasteners 404-410.

In the embodiment being described, the fasteners 404 and 408 comprise a head 404 b and 408 b that have a planar or flat portion 404 b 1 and 408 b 1 as shown. As best illustrated in FIGS. 34 and 35, note that the fasteners 408 and 410 each comprise threads or a threaded portion, such as threads or portions 408 c and 410 c of fasteners 408 and 410, respectively. Note that a distance or small radius D1 between center C1 and edge, 408 b 1 in FIG. 34 is smaller than the distance or large radius D2 measured by the distance between center C1 and edge 408 b 1 in FIG. 34. The difference in the distances D1 and D2 facilitates defining a cam surface or lobe on the wall 408 b 2 whose use and purpose will be defined later herein.

In the embodiment being described, one or more of the heads 404 b, 406 b, 408 b and 410 b may comprise an indicia, such as a grind mark or other indicator 412 and 414 (FIG. 32), to facilitate and assist a user, such as a doctor, to identify the small radius portion D1 during a surgical procedure. Thus, the indicia 412 and 414 facilitate defining the surface associated with the flat portion, such as portion 404 b 1.

It should be understood that when the pairs of fasteners 404-406 and 408-410 are aligned such that the surfaces 404 b 1 and 408 b 1 and short or small radius portion D1 are situated in opposite or closest to wall 406 b of screw 406 and wall 410 b of screw 410 the adjacent fasteners 406 and 410 respectively, may be rotated and screwed into, for example, vertebrae 10, which will secure and retain the cover 400 over the graft area 38. Although not shown, the locking system of the present invention may comprise eccentric fasteners of screws having eccentric heads (i.e. where a head center is offset from a thread axis) and fasteners that are used with non-eccentric fasteners. For example, and as illustrated in FIG. 33, fasteners 404 and 408 may comprise the aforementioned eccentric, while adjacent fasteners 406 and 410, respectively, may be non-eccentric fasteners or screws.

In any event, the small radius portion D1 permits the adjacent fastener or screw such as screw 410, whether it has an eccentric or not, to be turned when the small radius portion D1 or flat portion 408 b 1 is situated in opposed relationship to the adjacent screw (as illustrated in FIGS. 32 and 34). For example, FIG. 34 illustrates that when the fasteners are aligned such that the indicia 414 are aligned as illustrated in FIG. 32, a gap G exists between the portions 408 d 1 and wall 410 d of screw 410 as shown. The gap G permits either or both of the fasteners 408 and 410 to rotate in either a counter-clockwise or clockwise direction during fastening and unfastening of the fasteners to the vertebrae as described earlier herein with the prior embodiments.

When it is desired to secure the cover 400 over the housing 32, the fasteners 404-408 are placed in the cover and aligned as illustrated in FIG. 32. The fasteners 404-408 are rotated and screwed into vertebrae 10 in a clockwise direction until it is seated. These fasteners 404 and 408 are then “backed out” less than a full turn until flat surface 404 b 1 and 408 b 1 are aligned as shown in FIG. 32. The surgeon may use the indicator 412 and 414 to perform this alignment. This alignment presents the gap G (FIG. 34), which permits the fastener 410 to be rotated in a clockwise direction until completely screwed into vertebrae 10.

Next, the adjacent fastener (406 for the 404-406 pair and 410 for the 408-410 pair) is inserted into opening 405 in cover 400 and in FIGS. 32 and 34 until they are fully seated into the vertebrae 10. For example, in the illustration shown in FIGS. 32 and 34, the fastener 408 is rotated in a clockwise direction with a tool, such a hex wrench (not shown) until it is fully seated into the vertebrae 10.

The fastener 408 is again rotated in the clockwise direction (as viewed) until the large radius portion D2 and the wall portion 408 b 2 engages and comes against the wall 410 b of the fastener 410.

It should be appreciated that when the fasteners 404-410 are secured in the locked position in the manner described, they facilitate retaining themselves in the locked position. For example, if fastener 410 begins to rotate in a counterclockwise direction (as viewed in FIG. 33) it will cause fastener 408 to rotate in a clockwise direction which, in turn, causes fastener 408 to tighten and resist the counterclockwise rotation of fastener 410. If fastener 410 would rotate, fastener 408 would screw deeper into the vertebrae 10.

FIG. 36 is an illustration similar to FIG. 11 showing the orientation and alignment of the cover 400 and fasteners 404-410 to the housing 32.

FIGS. 37-44D show further embodiments illustrating several different plates or covers, such as a plate or cover 500 (FIG. 37), 600 (FIG. 40A), 700 (FIG. 41A), 800 (FIG. 42A), 900 (FIG. 43A) and 1000 (FIG. 44A), each of which comprises an integral lock 501 similar to the integral lock 62 relative to the embodiment illustrated in FIGS. 21-23.

Referring to FIGS. 37, 38A-38E and 39A-39E, a system and method are shown for facilitating and retaining the plate or cover to the spinal bones, such as spinal bones 10, 12, 14 and 16. In this embodiment, the implant cover or plate 500 comprises the plurality of apertures 502, 504, 506, 508, 510, 512, 514 and 516, each of which are capable of receiving a screw 540. The plate 500 has a plurality of integral locks, resilient detents or flexible fingers 520, 522, 524, 526, 528, 530, 532 and 534 associated with the apertures 502-516 as shown. In this embodiment, note that each of the plurality of integral locks, resilient detents or flexible fingers 520, 522, 524, 526, 528, 530, 532 and 534 are integral with the plate 500 and are resilient and flexible as with the prior embodiments. For ease of description, the structure and function of one of the integral locks, resilient detents or flexible fingers and associated aperture, namely detent or finger 520 of plate 500 and aperture 502 will be described. However, it should be understood that the plurality of apertures and associated plurality of detents and flexible fingers in the embodiments shown in the embodiments in FIGS. 40A-44D are substantially the same in structure and function.

In the illustration shown in FIGS. 37-39I, notice that the plate or cover 500 comprises a plurality of screw-receiving areas, such as apertures 502 and 504. Notice in FIG. 38A that each of the plurality of resilient detents or flexible fingers, such as finger 520, are defined by a cut-out portion, channel or area, such as area 529, that facilitates defining the resilient detent or flexible finger 520. Notice also that the cut-out area or channel 529 is in communication with the screw-receiving aperture or area 502 and also the window area 521 as shown. Notice that the channel area 529 is generally curved or arcuate and the resilient detent or flexible finger 520 comprises a similar or complementary curved or arcuate shape. It should be understood that the channel 529 enable the plurality of resilient detents or flexible fingers, such as fingers 520 and 522, to move toward and away from an axis of its the screw-receiving aperture or area, such as areas 502 and 504, respectively. A plurality of cut-out areas, apertures or channels, such as areas 527 and 529, are in communication with the areas 502 and 504, respectively, and facilitate providing or defining the plurality of resilient detents or flexible fingers 520 and 522, respectively. As with embodiments previously described, note that the integral portion 520 a is integrally formed into plate 500, so the plate 500 and integral fingers are a one-piece construction, as with the embodiment shown and described relative to FIGS. 21-23. Also, as with the embodiment illustrated in FIGS. 21-23, note that each resilient detent or flexible finger 520 is capable of flexing or moving toward and away from aperture 502 as will be described later herein. Note that the screw 540 comprises the screw head 540 a that comprises a camming portion 540 a 1 and a shoulder portion 540 a 2 as shown.

Each of the plurality of resilient detents or fingers, such as finger 520 in FIGS. 37 and 38A, comprises an integral portion 520 a that is integral with the plate 500, a detent portion 520 b, and a joining portion 520 c that joins the detent portion 520 b and integral portion 520 a as shown. In this embodiment, notice that the detent portion 520 b is situated toward an end 520 d of the resilient detent or finger 520. Note that each of the plurality of resilient detents or flexible fingers 520, 522, 524, 526, 528, 530, 532 and 534 are not linear and the joining portion 520 c comprises the curved or arcuate shape mentioned earlier, which facilitates or causes the detent portion 520 b to become operatively positioned in or near the screw-receiving aperture 502 as shown. Thus, each resilient detent or finger 520 comprises a configuration and shape that causes the detent portion 520 b to be associated with at least one of the apertures or screw-receiving areas, such as screw-receiving area 546, as shown. Note that each of the screw-receiving apertures or areas 502-516 each have at least one of the resilient detents or flexible fingers 520-534, respectively, associated therewith as shown. As mentioned earlier, the screw-receiving area 502 is capable of receiving a screw 540 that secures or fastens the plate 500 to the spinal bone 10 in the illustration in FIG. 37

Each plate or cover 500 may comprise at least one or a plurality of windows, such as windows 521, 523 and 525 (FIGS. 37 and 38A), in an interior area 500 c of the plate 500. The at least one or plurality of windows 521, 523 and 525, enable the surgeon to view the grafting areas, such as areas 26, 28 and 30 in FIG. 16, during the surgical procedure.

In the embodiment illustrated in FIG. 37-39I, the plate or cover 500 comprises a first end 500 a, a second end 500 b and the interior portion 500 c that joins the first and second ends 500 a and 500 b. In the embodiment illustrated, a first pair of resilient detents or fingers, namely fingers 520 and 522, is situated toward the first end 500 a in association with apertures 502 and 504, respectively, as shown. A second pair of resilient detents or fingers 532 and 534 is situated toward the second end 500 b in association with apertures 514 and 516, respectively. FIG. 37 illustrates two other pairs of resilient detents or flexible fingers 524, 526, 528, 530 and 532, 534, respectively. Note that the pairs, 524, 526 and 528,536 are situated in the interior area or portion 500 c of plate 500.

Referring to FIG. 37, 38A, 39B, 39C, 39E, 39F, 39H and 39I, the aperture 502 is defined by a generally cylindrical wall 546 defining a circumference that is not endless. The wall 546 terminates at an open area or opening 547. Notice that the resilient detent or flexible finger 520 is configured and comprises the shape mentioned earlier that facilitates causing detent portion 520 b to become operatively positioned in or associated with the opening 547 so that it can cooperate with and/or engage the screw 540 to retain and lock the screw 540 in the plate 500, thereby preventing the screw 540 from backing out of the spinal bone 10 to which it is secured. The plate 500 also comprises a second wall 542 having a smaller diameter than the wall 546. The second wall 542 also terminates at the opening 547 and provides a shoulder 544 that defines a seat that engages and supports a bottom portion 540 a 3 of screw head 540 a. Notice that in the illustrations shown in FIGS. 37-42D, it is contemplated that a screw 540 be inserted into each of the screw-receiving apertures. The operation of the resilient detent or flexible finger 520 and screw 540 will now be described.

As mentioned earlier, the plate or cover 500 comprises the screw-receiving aperture or area 502 that receives the screw 540 as shown in FIG. 39D. As the screw 540 is screwed into the spinal bone 10, the screw 540 moves or is screwed in the direction of arrow D in FIG. 39D. As the screw 540 moves in the direction indicated by arrow D, notice that a bottom portion 540 a 3 of screw head 540 a engages a top surface 520 e of the resilient detent or flexible finger 520, as illustrated in FIGS. 39D-39E. In the illustration being described, notice in FIGS. 39B, 39C, 39F and 39I, that the detent portion 520 b is generally L-shaped in cross-section and comprises the first leg portion 520 b and the second leg portion 520 b 2. As the screw 540 continues to be screwed into the spinal bone 10, a shoulder 540 a 2 of screw head 540 a engages a side wall 520 b 1 of the second leg portion 520 b 4 of locking or detent portion 520 b and forces it to move or flex in the direction of arrow E in FIG. 39D. It should be understood that each of the plurality of resilient detents or flexible fingers, including the finger 520, in plate 500 is generally biased to a home position, illustrated in FIGS. 37, 38A and 39A-39C. As the screw 540 moves farther into aperture 502, the finger 520 is caused to flex or move away from its home position. In this regard, notice that the camming portion 540 a 1 of screw head 540 a defines or provides a rounded engaging or camming surface that acts against and engages the flexible fingers 520 and forces it to move in the direction of arrow E, as illustrated in FIG. 39D.

After the portion or surface 520 b 2 of detent portion 520 clears the shoulder 540 a 2 of the screw head 540 a, as illustrated in FIGS. 39G, 39H and 39I, the generally planar portion or surface 520 e of detent portion 520 b flexes, moves or returns in a direction opposite arrow E (FIG. 39D) and toward the home position, at which time the surface 520 b 1 comes into proximity with or engages a generally cylindrical wall 540 a 3 of screw head 540 a. Notice in FIG. 39D that the wall 520 b 1 may have a curvature or curved surface that generally corresponds to a circumference or curvature of the cylindrical wall 540 a 3 in order to facilitate enabling the head 540 a to be screwed or rotated while the wall 540 a 3 engages, rides along or follows the surface 540 a 3.

A bottom surface 520 b 2 (FIG. 39C, 39E, 39F and 39I) of the detent portion 520 b becomes operatively associated with and opposed to the shoulder 540 a 2, as illustrated, for example, in FIGS. 39C, 39F and 39I. Notice that the dimension SD (FIG. 39F), which is a width of the shoulder 540 a 2, generally corresponds to a dimension DD (FIG. 39F), which is a cross-sectional width of a portion of the detent portion 520 e.

After the resilient detent or flexible finger 520 moves, flexes or returns to the home position illustrated in FIGS. 39A and 39B, the surface 520 b 2 of leg portion 520 b becomes operatively related and generally opposed to the shoulder 540 a 2 as shown, thereby locking the screw 540 to the plate or cover 500 and retaining the screw 540 in a locked position in the spinal bone, such as the spinal bone 10, so that it cannot back out of either the plate 500 or the spinal bone 10 to which it is attached.

In the embodiment being described, and as mentioned earlier, the plurality of the resilient detents or flexible fingers 520-534 are provided in a plurality of pairs, such as the pairs 520, 522; 524, 526; 528, 530; and 532, 534 as shown in FIG. 37. In the illustration being described relative to FIGS. 37 and 38A-38E, each of the resilient detents or flexible fingers making up the pairs is associated with at least one of the plurality of apertures 502-516, respectively, as shown.

The plate or cover 500 further comprises the plurality of windows or window areas 521, 523 and 525 mentioned earlier. Note that each of the plurality of window areas 521, 523 and 525 are defined or bounded at least in part by at least one or a plurality of the resilient detents or fingers 520-534 in the illustration being shown. For example, one or more of the window areas 521, 523 and 525 may be bounded by and in communication with the integral portion 520 a and joining portion 520 c of one or more of the resilient detent or flexible fingers 520-534. Thus, as illustrated in FIG. 38A, notice that the area or window area 521 is bounded or defined at least in part by the walls 500 e, 500 f, 500 g and 500 h and also the surfaces or walls 520 a 1 and 522 a 1. Likewise, the middle window 523 is bounded by the surfaces or walls 524 a 1, 526 a 1, 500 i, 530 a 1, 528 a 1 and 500 j. Alternatively, notice in the embodiment shown in FIG. 42A, an interior window 837 may be provided that is not partially bound by any portion of any resilient detent or fingers.

One advantage or feature of the windows, such as window area 531, is that it permits easy access and visualization to the associated graft area, such as area 28.

In the illustration being described, the plate or cover 500 may be curved or crowned along its length (FIG. 38C) and/or its width (FIG. 38D) to conform or complement the shape of the spinal bones 10-16. Notice that a front side 500 d of plate 500 may be generally smooth and have a curved or beveled edge 548 (FIG. 38C) as shown. A back or rear side 500 e (FIG. 38B) may comprise serrated areas 549 that facilitate retaining the plate or cover 500 in a secure position against the spinal bones 10-18. FIG. 38E illustrates a cross-sectional, enlarged and fragmentary view of the serrated areas 549.

It should be understood that the plate 500 may be provided with less or more apertures and associated resilient detents or fingers, and FIGS. 40A-44D illustrate several other illustrative embodiments. Similar parts and components in these embodiments bear the same part number, except that part numbers in the other embodiments are incremented by 100. For example, the shoulder 544 in FIG. 38A is substantially the same and operates in the same manner as the shoulder 644 in FIG. 40A.

In the illustration shown in FIG. 40A-40D, notice that plate 600 comprises two pairs of apertures 602, 604 and 614, 616. The apertures 602, 604, 614 and 616 have associated pairs of resilient detents or flexible fingers, namely, fingers 620, 622, 632 and 634, respectively, as shown. Thus, each of the screw-receiving apertures or openings in this embodiment has a corresponding resilient detent or finger associated therewith, as with the other illustrative embodiments. Notice in the embodiment illustrated FIGS. 40A-40D that the plate or cover 600 comprises only one open area or window 623 defined at least in part by the joining portions 620 c, 622 c, 632 c and 634 c. This embodiment may be useful, for example, when affixing the plate or cover to just two adjacent bones.

FIGS. 41A-41D are yet another illustrative embodiment showing a plate or cover 700 having three pairs of apertures 706, 708; 710, 712; and 714, 716, with each aperture having an associated resilient detent or flexible fingers 724, 726, 728, 730, 732, and 734, as shown. Notice that each of the screw-receiving apertures or areas 806, 808, 810, 812, 814, 816 is in communication with at least one window, such as windows 823 and 825.

FIGS. 42A-42D illustrate another embodiment with five pairs of aperture, namely apertures 806, 808; 810, 812; 814, 816; 806, 808; and 810, 812 with each aperture having an associated resilient detent or finger 820, as shown.

Thus, it should be understood that the plate or cover may have more or fewer screw-receiving apertures, resilient detents or flexible fingers and windows depending upon the application. Although not shown, some of the apertures may be provided without a resilient detent or finger or with multiple resilient detents or fingers, although it is preferred and each screw-receiving aperture or area has an associated detent, lock or finger. Also, the plate or cover may be provided with more or fewer windows 821, 823 and 825.

In the illustrations being described, note that each of the screw-receiving apertures, and associated detents, such as aperture 502 and detent 520 in FIG. 37, is in communication with at least one window. For example, note that the window 521 in FIG. 37 is in communication with the screw-receiving apertures or areas 502 and 504. Note that the bottom window 725 in FIG. 41A is in communication with the bottom pair (as viewed in FIG. 41A) of screw-receiving apertures or areas 714 and 716 as shown.

The embodiments illustrated in FIGS. 37-39I, 40A-40D and FIGS. 41A-41D are suitable for use as prosthetic implants that will be secured into multiple spinal bones, such as spinal bones 10 and 12 or spinal bones 10, 12 and 14 (FIG. 37). These illustrations contemplate that a plurality of pairs of screws 540 will be used to secure the plate or cover to each spinal bone, such as spinal bones 10, 12, 14 and 16 (FIG. 37). However, a plate and an integral lock that utilizes a single screw for each spinal bone is also contemplated. This will now be described relative to FIGS. 43A-44D.

As illustrated in the embodiment shown in FIGS. 43A-43D, the plate 900 comprises apertures 902 and 904. A plurality of integral resilient detents or flexible fingers 920 and 922, respectively, are configured and have detent portions 920 b and 922 b that are operatively associated with the apertures 902 and 904 as shown. As with prior embodiments, the resilient detents or flexible fingers 920 and 922 comprise the same components and are formed and function in the same manner as the finger 520 described earlier. The fingers 920 and 922 provide integral locks for retaining the screw, such as screw 540, in the locked position in the plate 900 and spinal bone, such as spinal bone 10, 12, 14 or 16 illustrated in FIG. 37.

FIGS. 44A-44D illustrate yet another embodiment wherein the plate 1000 comprises a plurality of apertures 1002, 1004 and 1006 as shown. Notice that the apertures 1004 and 1006 are in communication with a window 1021. As with the embodiment described earlier relative with FIGS. 43A-43D, notice the embodiment shown in FIGS. 44A-44D also comprise the plurality of resilient detents or flexible fingers 1020 and 1022, respectively, that are in operative relationship with the plurality of screw-receiving areas or apertures 1004 and 1006, respectively as shown. As with the illustration shown in FIG. 43A, each of the plurality of resilient detents or flexible fingers, such as finger 1020, comprises the integral portion 1020 a, a detent portion 1020 b and a generally curved joining portion 1020 c as shown. The plurality of resilient detents or flexible fingers 1020, 1022 and 1034 and associated components, such as components 1020 a-1020 c associated with finger 1020 function in substantially the same manner as the resilient detents or fingers 520 and associated components shown and described earlier relative to FIG. 37.

Advantageously, the embodiments illustrated in FIGS. 43A-43D and FIGS. 44A-44D provide plates or covers 900 and 1000 that utilize a single screw 540 to secure the plate or cover 900 and 1000 to each of the spinal bones, such as spinal bones 10, 12, 14 or 16, while also having at least one integral lock, resilient detent or flexible finger 920, 1020 associated with each screw 540 for retaining or locking the screw 540 in the plate or cover. As with embodiments illustrated in FIGS. 37-42D, the embodiments illustrated in FIGS. 43A-44D may optionally include at least one window, such as window 1021 shown in FIG. 44A, mentioned earlier, that are in communication with one or more of plurality of screw-receiving areas or apertures.

Advantageously, the illustrations in FIG. 37-44D show a one-piece integral plate comprising at least one or a plurality of integral locks manufactured from a single material to provide a one-piece plate. The plate may be made from titanium, titanium alloy, carbon fiber, polymer or other biocompatible material.

Advantageously, the various embodiments of the invention provide a system and method for inserting graft material 32 into a graft area 34 and 36 (FIG. 17) to fuse a plurality of bones such as bones 10-18 together. The system and method also provide means for fixing the bones 10-18 relative to each other, while permitting the housing 32 to cooperate with adjacent bones 10-18 to define a graft area 34 and 36 (FIG. 17) and to also float relative to the cover 42. The locking system illustrated in FIGS. 21-23 further facilitates providing a locking system that does not require the use of any tools, yet prevents back out of the screws 46.

While the apparatus and method described constitute preferred embodiments of this invention, it is to be understood that the invention is not limited to this precise apparatus and method, and that changes may be made in either without departing from the scope of the invention, which is defined in the appended claims. 

The invention claimed is:
 1. An implant plate comprising: a plate member having a plurality of apertures, each of said plurality of apertures being capable of receiving a screw having at least one surface; a plurality of resilient members having a locking portion in operative relationship with said plurality of apertures, respectively; and each of said plurality of resilient members retaining or maintaining said screw in a locked position; each of said plurality of resilient members being resilient and having a detent associated with at least one of said plurality of apertures; at least a portion of said screw engaging at least one of said plurality of resilient members and urging it open in response to axial movement of said screw; said at least one of said plurality of resilient members being resilient to cause said detent to move in a first direction away from an axis of said screw in response to engagement by said at least a portion of said screw and said axial movement of said screw and further enabling said detent to move in a second direction generally opposite said first direction so that a first portion of said detent becomes generally opposed to a first surface of a screw head and a second portion of said detent becomes generally opposed to a second surface of said screw head, wherein said first portion of said detent and said second portion of said detent are generally perpendicular or generally L-shaped.
 2. The implant plate as recited in claim 1 wherein said plurality of resilient members are integrally formed with said plate member.
 3. The implant plate as recited in claim 1 wherein said plurality of resilient members are non-linear.
 4. The implant plate as recited in claim 1 wherein said plurality of resilient members each comprise an arcuate portion between a first portion, which is integrally connected to said plate member, and said locking portion.
 5. The implant plate as recited in claim 1 wherein each of said plurality of resilient members moves toward and away from its respective plurality of apertures in response to a camming portion of said screw.
 6. The implant plate as recited in claim 1 wherein said plate member comprises at least one window area.
 7. The implant plate as recited in claim 1 wherein said locking portion is located at an end of each of said plurality of resilient members.
 8. The implant plate as recited in claim 1 wherein said plate member comprises an even number of integrally formed plurality of resilient members.
 9. The implant plate as recited in claim 1 wherein said plate member comprises a first end, a second end and a joining portion joining said first and second ends; said implant plate further comprising: a first pair of said plurality of apertures located toward said first end of said plate member; a first pair of said plurality of resilient members extending from said joining portion and toward said first pair of said plurality of apertures, respectively, such that their respective locking portions become situated adjacent said first pair of said plurality of apertures.
 10. The implant plate as recited in claim 9 wherein said first pair of said plurality of resilient members are adjacent each other.
 11. The implant plate as recited in claim 1 wherein said implant plate comprises at least one window in communication with each of said plurality of apertures.
 12. The implant plate as recited in claim 11 wherein said at least one window is bounded at least in part by said plurality of resilient members.
 13. The implant plate as recited in claim 1 wherein each of said plurality of resilient members comprises a curved portion and a detent portion, said detent portion being situated in operative relation to one of said plurality of apertures.
 14. The implant plate as recited in claim 1 wherein each of said plurality of resilient members comprises detent portion that follows or engages a wall of a head of said screw after it is received in a spinal bone.
 15. The implant plate as recited in claim 1 wherein said plurality of apertures and said plurality of resilient members are arranged and adapted such that at least two screws can be used for each spinal bone.
 16. The implant plate as recited in claim 1 wherein said plurality of apertures and said plurality of resilient members are arranged and adapted such that a single screw is used for each spinal bone.
 17. The implant plate as recited in claim 1 wherein said implant plate comprises an odd number of said plurality of apertures.
 18. The implant plate as recited in claim 1 wherein said implant plate comprises an even number of said plurality of apertures.
 19. An implant plate comprising: at least one screw receiving aperture; and at least one integral lock associated with said at least one screw receiving aperture for preventing a screw received in said at least one screw receiving aperture from withdrawing from said implant plate; said at least one integral lock comprising at least one flexible member having a detent associated with said at least one screw receiving aperture; at least a portion of said screw engaging said at least one flexible member and causing it to move in said at least one screw receiving aperture in response to axial movement of said screw; said at least one flexible member being resilient to enable said detent to move in a first direction away from an axis of said screw in response to engagement by said at least a portion of said screw and said axial movement of said screw and further to enable said detent to move in a second direction generally opposite said first direction so that a first portion of said detent becomes generally opposed to a first surface of a screw head and a second portion of said detent becomes generally opposed a second surface of said screw head after said screw is screwed into bone; said at least one flexible member being urged to or biased to a home position after said screw is screwed into bone so that said first portion of said detent becomes generally opposed to said first surface of said screw head and said second portion of said detent becomes generally opposed to said second surface of said screw head; wherein said first portion of said detent and said second portion of said detent are generally perpendicular or generally L-shaped.
 20. The implant plate as recited in claim 19 wherein said at least one screw receiving aperture defines a plurality of screw-receiving areas, said at least one comprising a plurality of flexible members associated with said at least one screw receiving aperture, respectively.
 21. The implant plate as recited in claim 1 wherein said plurality of resilient members comprises a locking portion and a flexible or resilient portion that permits said locking portion to flex or move toward and away from said plurality of apertures.
 22. The implant plate as recited in claim 20 wherein said at least one integral lock comprises a locking portion and a flexible or resilient portion that permits said locking portion to flex or move toward and away from said at least one of said plurality of screw-receiving areas.
 23. An implant plate comprising: a plate member having a plurality of screw-receiving areas, each of said plurality of screw-receiving areas being capable of receiving a screw having at least one generally radial surface; and a plurality of locking fingers associated with said plurality of screw-receiving areas, respectively, each of said plurality of locking fingers being capable of retaining said screw in at least one of said plurality of screw-receiving areas; each of said plurality of locking fingers having an end associated with said at least one of said plurality of screw-receiving areas; each of said plurality of locking fingers having a detent proximate said end that moves in a first direction away from an axis of said screw in response to engagement by at least a portion of said screw and an axial movement of said screw and further to enable said detent to move in a second direction generally opposite said first direction so that a first portion of said detent becomes generally opposed to a first surface of a screw head and a second portion of said plurality of locking fingers becomes generally opposed to a second surface of said screw head after said screw is screwed into bone; wherein said first portion of said detent and said second portion of said detent are generally perpendicular or generally L-shaped.
 24. The implant plate as recited in claim 23 wherein said plurality of locking fingers are integrally formed in said plate member.
 25. The implant plate as recited in claim 23 wherein each of said plurality of locking fingers comprises a locking tab for engaging a head of a screw and causing said screw to be retained in a locked position.
 26. The implant plate as recited in claim 23 wherein each of said plurality of locking fingers is flexible.
 27. The implant plate as recited in claim 23 wherein said plurality of locking fingers each comprise a curved portion between a first portion which is integrally connected to said plate member and a detent portion.
 28. The implant plate as recited in claim 23 wherein each of said plurality of locking fingers moves toward and away from said plurality of screw-receiving areas.
 29. The implant plate as recited in claim 23 wherein said plate member comprises at least one window area.
 30. The implant plate as recited in claim 23 wherein each of said plurality of locking fingers comprises a locking portion located toward an end thereof.
 31. The implant plate as recited in claim 23 wherein said plate member comprises a window area bounded at least in part by at least one of said plurality of locking fingers.
 32. The implant plate as recited in claim 23 wherein said plate member comprises a first end, a second end and a joining portion joining said first and second ends; said implant plate further comprising: a first pair of said plurality of screw-receiving areas located toward said first end of said plate member; a first pair of said plurality of locking fingers extending from said joining portion and toward said first pair of said plurality of screw-receiving areas, respectively, such that their locking portion becomes situated adjacent said first pair of said plurality of screw-receiving areas, respectively.
 33. The implant plate as recited in claim 32 wherein said first pair of said plurality of locking fingers are adjacent each other.
 34. The implant plate as recited in claim 23 wherein said plurality of screw-receiving areas each comprises an associated seat for engaging a bottom portion of a head of said screw.
 35. The implant plate as recited in claim 34 wherein said associated seat is not continuous.
 36. The implant plate as recited in claim 23 wherein a plurality of said plurality of screw-receiving areas are in communication with each other.
 37. The implant plate as recited in claim 29 wherein a plurality of said plurality of screw-receiving areas are in communication with each other and said at least one window area.
 38. The implant plate as recited in claim 29 wherein said plate member is titanium, titanium alloy, carbon fiber, polymer or other biocompatible material.
 39. An implant system comprising: a plate member having a plurality of screw-receiving openings; a plurality of locking fingers adjacent said plurality of screw-receiving openings, respectively; and a plurality of screws received by said plurality of screw-receiving openings, respectively, and retained in said plate member by said plurality of locking fingers, each of said plurality of screws having at least one generally radial surface; each of said plurality of locking fingers being resilient or flexible and having a detent associated with at least one of said plurality of screw-receiving openings; each of said plurality of locking fingers having a detent that moves in a first direction away from an axis of at least one of said plurality of screws in response to engagement by at least portion of said at least one of said plurality of screws and an axial movement of said at least one of said plurality of screws and further to enable said detent to move in a second direction generally opposite said first direction so that a first portion of said detent becomes generally opposed to a first surface of a screw head and a second portion of said plurality of locking fingers becomes generally opposed to a second surface of said screw head after said at least one of said plurality of screws is screwed into bone; wherein said first portion of said detent and said second portion of said detent are generally perpendicular or generally L-shaped.
 40. The implant system as recited in claim 39 wherein said plurality of locking fingers are integrally formed in said plate member.
 41. The implant system as recited in claim 39 wherein each of said plurality of locking fingers comprises a locking portion for engaging a head of a screw and causing said at least one of said plurality of screws to be retained in a locked position in said plate member.
 42. The implant system as recited in claim 39 wherein each of said plurality of locking fingers are flexible.
 43. The implant system as recited in claim 39 wherein each of said plurality of locking fingers comprises a first portion that is integrally connected to said plate member, a locking portion and a flexible portion joining said first portion and said locking portion.
 44. The implant system as recited in claim 39 wherein each of said plurality of locking fingers moves toward and away from said plurality of screw-receiving openings to which it is adjacent.
 45. The implant system as recited in claim 39 wherein said plate member comprises at least one window area situated internally in said plate member.
 46. The implant system as recited in claim 39 wherein each of said plurality of locking fingers comprises a locking portion located toward an end thereof.
 47. The implant system as recited in claim 39 wherein said plate member comprises a window area defined at least in part by at least one of said plurality of locking fingers.
 48. The implant system as recited in claim 39 wherein said plate member comprises a first end, a second end and a joining portion joining said first and second ends; said implant system further comprising: a first pair of said plurality of screw-receiving openings located toward said first end of said plate member; a first pair of said plurality of locking fingers extending from said joining portion and toward said first pair of said plurality of screw-receiving openings, respectively, such that their respective locking portions become situated adjacent said first pair of said plurality of screw receiving openings.
 49. The implant system as recited in claim 48 wherein said first pair of said plurality of locking fingers are adjacent each other.
 50. The implant system as recited in claim 39 wherein said plurality of screw receiving openings is defined, at least in part, by an associated seat in said plate member.
 51. The implant system as recited in claim 50 wherein said associated seat is not endless and opens to a locking finger area, at least one of said plurality of locking fingers being situated in said locking finger area.
 52. The implant system as recited in claim 39 wherein a plurality of said plurality of screw-receiving openings are in communication with each other.
 53. The implant system as recited in claim 45 wherein a plurality of said plurality of screw-receiving openings are in communication with each other and also with said at least one window area.
 54. The implant system as recited in claim 39 wherein each of said plurality of screws comprises a shoulder portion and a camming portion, said camming portion causing at least one of said plurality of locking fingers to flex away from its associated screw-receiving area and said shoulder portion engaging said at least one of said plurality of locking fingers and retaining said screw in a substantially locked position.
 55. An implant plate system comprising: a plate member; and a plurality of locks integrally formed in said plate member for retaining a plurality of screws, respectively, in said plate member; each of said plurality of locks being flexible and having a detent; each of said plurality of locks having a detent that moves in a first direction in response to engagement by at least a portion of said plurality of screws and an axial movement of at least one of said plurality of screws and further to enable said detent to move in a second direction generally opposite said first direction so that a first portion of detent becomes generally opposed to a first surface of a screw head and a second surface of said plurality of locks becomes generally opposed to a second portion of said screw head after said at least one of said plurality of screws is screwed into bone; wherein said first portion of said detent and said second portion of said detent are generally perpendicular or generally L-shaped.
 56. The implant plate system as recited in claim 55 wherein said plurality of locks comprise a plurality of flexible fingers.
 57. The implant plate system as recited in claim 56 wherein each of said plurality of flexible fingers comprises a locking portion that prevents a screw from backing out after it is screwed into a spinal bone.
 58. The implant plate system as recited in claim 57 wherein each of said plurality of flexible fingers elastically deforms in response to engagement by said screw as it is being screwed into said spinal bone.
 59. The implant plate system as recited in claim 56 wherein said plate member is a one-piece construction and comprises a window area, at least one of said plurality of flexible fingers yielding toward and into said window area when a screw is being screwed into a spinal bone.
 60. The implant plate system as recited in claim 56 wherein said plurality of flexible fingers comprise a curved portion.
 61. The implant plate system as recited in claim 57 wherein said locking portion is generally located at an end of each of said plurality of flexible fingers.
 62. The implant plate system as recited in claim 61 wherein said locking portion is generally L-shaped in cross-section.
 63. The implant plate system as recited in claim 57 wherein said implant plate system comprises: a screw having a camming surface and a shoulder; said camming surface engaging said locking portion and moving said locking portion away from a screw-receiving area in said plate member when said screw is screwed; said locking portion also cooperating with said shoulder to retain said screw in a locked position.
 64. The implant plate system as recited in claim 57 wherein said locking portion is generally located at an end of each of said plurality of flexible fingers.
 65. The implant plate system as recited in claim 63 wherein said locking portion comprises a first portion and a second portion integrally formed with said first portion; and said shoulder generally lying in a shoulder plane after said screw is received in said screw-receiving area, at least one of said first or second portions lying at least partially over said shoulder in an engaging member plane that is generally parallel to said shoulder plane after said screw is received in said screw-receiving area.
 66. A prosthetic implant plate comprising: a generally planar member; and a plurality of integral locks for preventing withdrawal of at least one screw after said at least one screw is screwed into a spinal bone; each of said plurality of integral locks being resilient and flexible and normally biased in a closed position and having a detent; and each of said plurality of integral locks having a detent that moves in a first direction away from an axis of said at least one screw in response to engagement by a portion of a screw head of said at least one screw and an axial movement of said at least one screw and further to enable said detent to move in a second direction generally opposite said first direction so that a first portion of said plurality of integral locks becomes generally opposed to a first surface of said screw head and a second portion of said plurality of integral locks becomes generally opposed to a second surface of said screw head after said at least one screw is screwed into bone; said portion of said at least one screw engaging at least one of said plurality of integral locks and urging it open in response to axial movement of said at least one screw until said at least one of said plurality of integral locks causes said first portion of said detent to become generally opposed to said first surface of said screw head and said second portion of said detent becomes generally opposed to said second surface of said screw head; wherein said first portion of said detent and said second portion of said detent are generally perpendicular or generally L-shaped.
 67. The prosthetic implant plate as recited in claim 66 wherein each of said plurality of integral locks comprises an elongated resilient member integrally formed in said prosthetic implant plate; said elongated resilient member comprising a detent portion; and said elongated resilient member moving from a home position when it is screwed into a spinal bone, and returning to said home position after said at least one screw clears said detent portion.
 68. The prosthetic implant plate as recited in claim 66 wherein each of said plurality of integral locks is generally L-shaped in cross-section.
 69. The prosthetic implant plate as recited in claim 66 wherein said prosthetic implant plate is titanium. 